MagisterCultuum
Great Sage
Small nitpick: the limit only applies to the ability to the ability to summon more, not to how many you can have. Captured Tigers and Treants from the Ljosalfar worldspell or those that naturally appear to defend an ancient forest count against the limit too. If you lose a caster the extra permanent summons aren't lost. Twincast can get you over the limit by creating 2 summons even when you are only 1 away from the limit. I forget whether twincast makes that caster count as 2 for purposes of determining how many permanent summons you can have.
I've heard that there is a bug where not all the spells prereqs are checked in determining the number of potential casters. It checks for promotions, but not for religions. Thus, if you had 20 priests (or more generally units with Divine and Channeling 2) but only 1 of them was a Priest of the Leaves (or an upgrade thereof), then you could summon 20 Tigers.
I've heard that there is a bug where not all the spells prereqs are checked in determining the number of potential casters. It checks for promotions, but not for religions. Thus, if you had 20 priests (or more generally units with Divine and Channeling 2) but only 1 of them was a Priest of the Leaves (or an upgrade thereof), then you could summon 20 Tigers.